Well bore scraping device



Feb. 12, 1957 E. c. PYLE ETAL WELL BORE SCRAPING DEVICE Filed Aug. 1, 1955 )x lhll FIG.

l z FiLl- INVENTOR. sow/1v c. PYLE;

FIG. 4.

FORREST C. PITTMAN A TTORNEY.

United States Patent 6 WELL BORE SCRAPING DEVICE Edwin C. Pyle and Forrest C. Pittman, Duncan, Okla, assignors to Halliburton Oil Well Cementing Company,

Duncan, Okla Application August 1, 1955, Serial No. 525,548

7 Claims. cl. 166173) This invention relates to well bore scrapers and more particularly to a scraping device for removing mud cake from a well bore wall during cementing operations.

In the rotary method of drilling wells a mud is generally used to remove cuttings and also to deposit a cake on the wallsof the well bore in order to prevent fluid leakage into surrounding formations. After the well is drilled a casing is lowered into the well bore and cemented in place. This cementing operation usually consists of pumping a Portland cement slurry down through and out the bottom of the casing wherein the cement then flows upwardly in the annulus formed between the casing and well bore. The cement, when set, will bond the casing to the well bore walls. The success of this bonding depends to some extent upon the removal of the mud cake from the bore wall so that the cement slurry can directly contact the formation. Also dependent to some extent is the centering of the casing in the well bore and an even filling of the annulus with cement.

It has heretofore been proposed, as in the patent to Reistle, No. 2,421,434 and inthe patent to Edwards, No. 2,412,876, to employ various wire brushes or metal scrapers mounted on the casing to scrape the mud cake from the walls of the well bore. Such devices have been used and perform a desirable function. There have been disadvantages involved in their use however, inasmuch as construction of these devices is complicated, increasing their cost, and drilling cuttings or mud cake tend to deposit on and between their scraping members, hindering or causing channeling flow of the incoming cement slurry.

It is an object of the present invention to provide a well bore scraping device adapted to be lowered into a well bore in which the scraping members are circumferentially disposed about the casing and in which each member is mounted in such manner that it may perform the desired function of removing mud cake from the wall of the well bore even after being lowered thousands of feet to the bottom of the well.

It is another object of the invention to provide a scraping device having members of a molded homogeneous resilient material and so formed as to engage the walls of the well bore in relative movement of only one direction, these devices having one or more finger mem bers which engage the bore walls upon travel of the casing in this one direction.

In accordance with this invention, there is provided a reciprocating well bore scraping device having a plurality of finger members arranged around a well casing, each finger member being integrally formed of a resilient material and having an arm attached to the well casing at an angle acute relative to the axis of the casing, this arm terminating in an actuating element and at least one scraping element at its outer end, the scraping element being positioned normal to the arm and situated within the acute angle previously described, and said actuating element being adapted for frictional contact with a well bore wall whereby vertical movement of said 2,781,100 Patented Feb. 12, 1957 2 casing in the direction in which said arm is inclined relative to said casing will flex said arm in pivoted relation about said actuating element and transfer said scraping element from inside said acute angle out into contact with said well bore wall.

Other objects and advantages reside in certain novel features of the construction and arrangement as will be apparent from the following description taken in conuection with the accompanying drawings, in which:

Figure 1 is a sectional elevation of the scraping device as attached to a well casing in a well bore.

Figure 2 is a plan view of the scraping device as attached to a well casing.

Figure 3 is a sectional view of the scraping device as when the scraping elements of the device are in contact with the walls of the well bore.

Figure 4 is a sectionalview of an individual member of the scraping device.

Referring to Figure 1, it can be seen that a casing adapted to be used in a well bore 10 is illustrated at 12. Circumferentially mounted on the casing 12 are one or more of the scraping devices 14. Each device 14 has a plurality of finger members 16. The device 14 is made of rubber or similar elastic material and is of molded construction. 1

Supporting and longitudinally spacing the devices 14 are keeper rings 18 which are welded or otherwise attached to the well casing 12. In Figure 2 is shown the angular spacing of the finger members 16 about the easing 12.

Each finger member 16, as best shown in Figure 2, is attached to a base 20 vulcanized or otherwise attached to a supporting sleeve 22. Each finger member 16 has an arm 24 exteriorly formed with the base 20 at a suitable angle, preferably less than The arm 24 terminates in an actuating element 26, which action will be later described, and has, near its terminus, one or more scraping elements 28 and 28', formed at substantially right angles to the arm 24 and extending into the acute angle formed by the base 20 and the arm 24.

As the well casing is lowered into the well bore the finger members 16, as best depicted in Figure 1, are provided with arms 24 of such length and with such an angle formed by the arms 24 and the base 20, as to maintain frictional contact between actuating element 26 and the walls of the well bore 10.

In operation, the casing 12 is raised, the frictional contact of the actuating element 26 against the walls of well bore 10 causing the arm 24 to flex downwardly. Flexing of the arm 24 pivots the scraping elements 28 and 28 into scraping position against the well bore walls. Continued upward movement impels the scraping elements 28 and 28 along the walls of the well bore 10, thereby removing the mud cake encountered. This operating position is best shown in Figure 4. Subsequent lowering of the casing will revert the scraping elements 28 and 28 to the initial position of the arm 24, as shown in Figure 1.

It is noted that while Figures 1 and 2 illustrate only one unit of this invention, any desirable number of units may be used. When multiple units are used, they will be appropriately spaced along the casing in such a manner as to obtain complete coverage of the well bore walls during each scraping actuation of the casing.

With a scraping device constructed as illustrated and mounted on a well casing as shown, the casing may be lowered into the well with the scraping device sutfering little or no wear or damage, because, as the casing is lowered, the arms 24 of the finger member 16 fiex inward ly on demand, preserving and protecting the scraping elements-28 and 28' until their use is desired. Upon reaching a desired depth the casing is raised upwardly a short distance to actuate the scraping device.

Any number of reciprocations of the casings may be made as necessary to clean" the mud cake from the well bore walls, 'While'thistscraping-device; tends toicentrally locate the casing in the well bore, commercially available oentr'alizersimay heused in conjunctionifdesired.

With scraping devicesconstructed as illustrated and mounted on a casing as shown in Figure 1, any danger of the scraper becoming cloggedifromflupwardly flowing 'fiuids is obviated vby thertendency of the scraper memuse is therefore recommended.

Though only one embodiment ofthe invention has been illustrated and'described herein, it-is obvious that various changes may be madewithout'departing' from the spirit of the invention or thescope of theattached claims.

That being claimed is: 7

lJIn a well bore'scraping device for a well casing,

a plurality of resilient-integrally formed finger mem-i bers disposed around said casing, means of mountingsaid members to'said casing, each-of said members having an arm extending outwardly from said casing at an angle acute relative to the axis of'said;casing, said arm having at least one scraping element-formed substantially normal thereto and extending into said acute angle, said iarm terminating in an actuating element said actuating element being adapted for frictional contact with a well bore wall whereby vertical movement of said casing in the direction in which the arm is inclined relative to said casing will flex'said arm in pivoted relation about said actuating element and transfer said scraping element from inside said acute angle out into contact with said well bore wall.

2. In a Well bore scraping device for a well casing, a plurality of resilient integrally forme'dfinger members, each of said members having a base attached to a sleeve disposed around said casing, each ofisaid members'having an arm extending routwardlyifrom said ,base at an angle acute relative to the axis of said casing, said arm 4. In a well bore scraping device for a well casing, a plurality of resilient integrally formed finger members, means of mounting said members to said casing, said means including an attachment of said members to a having at least one scraping 'elementformed substantially 7 normal thereto and extending intoisaidacute angle, said arm terminating inan actuating element, said actuating clement beingadaptedfor frictional contact.with a well bore wall whereby verticalmovement of said casing in the direction in which the arm-is inclined relative to said casing will flex said arm in pivoted relation about said actuatingtelement and transfersaid scraping element, from inside saidracute angle out into contact with said 'well' bore wall. 7

3. In a well bore scraping device for a well casing, a plurality of molded homogeneous integrallyformed fingers membersymeans Ofmounting said members to said casing, each of said members having an arm extending outwardly from said casing at an angle acute relative to the axis of saidncasing, said arm having at a least one scrapingelement formed'substantially normal sleeve disposed about and'longitudinally fixed to said casing, each'of said members having an arm extending outwardly'from said casing at an angle acute relative to the axis of said casing, said arm having at least one scrapingelemenfformed substantially normal thereto and extending into said acute angle, said arm'terininating in an actuating element, said actuating element being adapted forfrictional' contact witha Well bore Wall-whereby vertical movement of said casing in thev direction in which the arm is inclined relative to said casing will flex said arm in pivoted relation about said actuating element and transfer said scraping element from inside said acute, angle out into contact with said well bore wall.

5. In a swell bore scraping device adapted to be attached to a well casing, comprising, a resilient'finger member, said member having an arm extending from a base at an angle acute relative tosaid base, said base having means to be attached to said casing, said arm having at least one scraping element formed substantially normal-to and extending into saidacuteangle, said arm terminatingin an actuating elemengsaidactuating element 'being'iadapted for frictional contact with a well bore wall whereby movement of said base relative'to said well bore wallin the direction in'which the arm is-inclined 'relative'to said base will flex said arm in' pivoted relation about saidactuating element and transfersaidscraping-element from inside said acute angleout into contact with said well'bore wall. g

6. An article of manufacture'suitable for scraping-well bores when attached to a well casing, comprising, a resilient integrally formed finger member, said member having an arm extending outwardly froma base atian angle acute relative to said base, said armhaving at least one scraping elementformed substantially normal to said arm and extending into said acute angle, said arm terminating in an actuating element, said actuating ele ment being adapted for frictional contact with a well bore wall, whereby movement of said finger member in parallel relation to said well bore Wall and in'the direction in which said arm is inclined relative to said base will wardly from a-base at an angle acute to'sai'd base, said 7 base having means of attaching said member to said casing, said arm having at least one scraping element formed substantially normal to said arm and extending into said' angle, said arm terminating in an actuating element,

-. said actuating element being adapted for frictional com tact with a Wall on the same plane as saidbase whereby movement of said base in parallel relation to said wall in the direction in which the arm is inclined relative to said base willifiex said arm in pivoted relation about said actuating element and transfer said scraping element from inside said acute angle out into scraping contact with said wall. 7

Bashara 1 June 8, 1920 Wright June 18, 1946 Garrison May 2-5, 1954 

